Automatic hydraulic governing system for steam turbines having several adjustable parameters



Sept. 16, 1969 v. N. VELLER ETAL 3,466,977

AUTOMATIC HYDRAULIC GOVERNING SYSTEM FOR STEAM TURBINES HAVING SEVERAL ADJUSTABLE PARAMETERS Filed March 10, 1967 B Sheets-Sheet 1 Sept. 16, 1969 v. N. VELLER ETA!- 3,466,977

AUTOMATIC HYDRAULIC GOVERNING SYSTEM FOR STEAM TURBINES HAVING SEVERAL ADJUSTABLE PARAMETERS Filed March 10, 1967 2 Sheets-Sheet 2 x \I L /0 H52 United States Patent US. Cl. 91-458 1 Claim ABSTRACT OF THE DISCLOSURE An automatic hydraulic governing system having several adjustable parameters and particularly for steam turbines in which stream-type summation devices are interposed between the transducers of the pressure signals and the amplifying units, and in which summation devices the summing of the incoming signals is effected on the principle of interaction between several streams of fluid.

The present invention relates to power facilities, and more particularly to automatic hydraulic governing systems for steam turbines having several adjustable parameters.

Automatic hydraulic governing systems for steam turbines having adjustable parameters are known, in which a coordinated control action is effected by summing the pressure pulses or signals from individual control means with the help of summing pilot valves. Each of the control means operates its own summing pilot valve which controls the flow of operating fluid from three pressure signal lines to drain outlets, thus transforming the magnitude and the direction of the control signal from the control means and feeding the transformed signal to the control valves of the main servomotors operating the steam supply regulators of the turbine (cf. the manual Governing of Steam Turbines by A. V. Shcheglyayev and S. G. Smelnitsky, Moscow, 1962, pp. 235 to 237).

However, these known governing systems are not free from certain disadvantages, namely, the high costs of their manufacture due to a considerable number of pilot valves which should be manufactured to the highest accuracy class; a comparatively high loss of operating pressure fluid in the system due to a great number of controllable drain outlets; and the influence of the rate-offlow factors of the controllable outlets upon the value of the summed signal, due to the fact that the summing of the transformed signals in the intermediate amplifying unit is effected by varying the effective size of the profile outlet ports in the valves.

It is an object of the present invention to overcome the abovementioned disadvantages.

It is a specific object of the present invention to provide a hydraulic governing system for a steam turbine having several adjustable parameters, which system is of a comparatively simple design and provides for summing the signals representative of these parameters without these signals being transformed in pilot valves.

Generally, the present invention is directed to an automatic hydraulic governing system having several adjustable parameters particularly for steam turbines, including transducers of signals in the hydraulic pulses of operating fluid, summation means for summing said pulses, actuating means controlled by output signals fed from said summation means, each of said summation means being defined according to the principle of non-submerged streams, each transducer including means defining a hollow body, two rigidly interconnected parallel 3,466,977 Patented Sept. 16, 1969 diaphragms, one of said diaphragms being inperforate and the other having an opening therethrough, said diaphragms being arranged in said hollow body, control deflectors secured on said diaphragms, and two stationary nozzles of equal cross-sectional area, the perimeter of cross-section differing in the case of each nozzle, said nozzles being installed in said hollow body between said diaphragms, the uncontrolled pulse being supplied into the space under said imperforate diaphragm, said operating fluid to said nozzles, and said transform pulse from the space of said hollow body separated by said imperforate diaphragm from the side opposite to the feed of said control pulse.

The present invention may be better understood from the following detailed description of an embodiment thereof, and due reference is made to the accompanying drawings, in which:

FIG. 1 is a diagrammatic view of an automatic hydraulic governing system for a steam turbine having three adjustable parameters, and the steam turbine controlled by this system;

FIG. 2 is a longitudinal sectional view of the diaphragm-type signal transducer; and

FIG. 3 is a cross-sectional view of the stream-type summation device.

A hydraulic governing system for a steam turbine 1 (FIG. 1), embodying the present invention, comprises turbine shaft speed-responsive means 2 in the form of a centrifugal oil pump mounted on the turbine shaft, with the discharge pressure of this pump being thus propor tional to the square r.p.m. number of the turbine rotor. The oil pump may be used simultaneously for supplying oil for lubrication purposes.

The pressure value derived from the pump 2 (i.e. the pressure signal) is fed via a diaphragm-type transducer 3 to nozzles 4, 5 and 6 of stream-type summation devices 7, 8 and 9, respectively, The transducer 3 functions also as a separator of the two fluids, namely, the oil coming along a conduit 10 and the water leaving the transducer along a conduit 11.

When the value of the pressure signal P coming from the turbine shaft speed responsive means 2 into the transducer 3 along the conduit 10 varies, the previously established equilibrium of forces acting upon two diaphragms 12 and 13 (FIG. 2) is upset, which results in the deformation of the diaphragms, whereby the clearances (the throttling areas) between nozzles 14, 15 and deflectors 14', 15 adjacent thereto vary accordingly. With the throttling area corresponding to the upper nozzle 14 (i.e. the one with the annular outlet) being several times greater than the throttling area corresponding to the lower nozzle 15 (i.e. with the circular outlet), the direction of change of the transformed signal P is defined by the direction of change in the clearance between the upper nozzle 14 and the deflector 14'.

The process of deformation of the diaphragms 12 and 13 continues until the value of the transformed pressure signal P corresponds to the now established value of the pressure signal P The diaphragm-type transducer 3 serves to compensate for the influence of the pressure P of the operating fluid system upon the value of the transformed pressure signal P due to the equality of the outlet cross-sectional areas of the nozzles 14 and 15.

The pressure signals P and P (FIG. 1) representative of the pressure of the steam exhausted by the corresponding turbine stages is supplied directly from respective exhaust conduits 16 and 17 to corresponding transducers 18 and 19, from which the transformed pressure signal P and P are fed to the stream-type summation devices 7, 8 and 9.

In each one of the three stream-type summation devices 7, 8 and 9 the operating fluid coming from the transducer 3 is supplied to the discharge nozzles 4, and 6, respectively, which discharge nozzles eject streams of fluid toward oppositely disposed intake nozzles 20, 21 and 22, respectively.

The pressure fluid coming from the transducer 18, i.e. the one supplied with the pressure signal P representative of the exhaust pressure of the first stage is fed to nozzles 23, 24 and 25 in the three summation devices, while the pressure fluid coming from the transducer 19, i.e. the one supplied with the pressure signal P representative of the exhaust pressure of the second stage is fed to nozzles 26, 27 and 28. The streams of fluid ejected by the nozzles 23, 24, 25, 26, 27 and 28 are directed upon the respective main streams, ejected by the nozzles 4, 5 and 6, representing the speed-responsive pressure signals (FIG. 3). The interaction of these streams lead to corresponding variations in the pressure of fluid received by the intake nozzles 20, 21 and 22 (FIG. 1), with the direction of the variations depending on the relative posi tions of the nozzles in the summation devices.

The summed signal pressure P, acts upon a springbiased piston 29 of a hydraulic amplifying unit 30, whereby a stop valve 31 rigidly connected to the piston 29 is displaced. The stop valve 31 controls the operation of a double-action servomotor 32 which also serves as the stop valve of a hydraulic piston-and-cylinder actuator 33 displacing a device 34 controlling the supply of steam to the high-pressure portion of the turbine.

In a way similar to the one described in the foregoing paragraph, the summed pressure signals P and P from the summation devices 8, 9 are fed to amplifying units 35, 36 and thus control the actuators displacing steam supply control devices 39 and 40, respectively, of the medium-pressure and the low-pressure portions of the turbine.

What is claimed is:

1. An automatic hydraulic governing system having several adjustable parameters, particularly for steam turbines having a shaft, comprising means responsive to the turbine shaft speed for producing pressure signals in an operating pressure fluid, a plurality of transducers one of which being operatively connected to transform the pressure signals derived from the means responsive to the turbine shaft speed, plural summation means operably related to each transducer for receiving signals sent by the transducers, actuating means controlled by signals emanating from one of said summation means, each summation means including a body having discharge nozzles operatively connected for receiving operating fluid from the transducers and an oppositely disposed intake nozzle for receiving fluid from the discharge nozzles with the pressure signal from the intake nozzle serving to actuate the actuating means, each transducer including means defining a hollow body, two rigidly interconnected parallel diaphragms arranged in said hollow body, one of said diaphragms being imperforate and the other diaphragm having an opening therethrough, a control deflector secured to each diaphragm, two stationary nozzles installed in said hollow body between said diaphragms, one of said nozzles having an annular outlet and the other nozzle a circular outlet, said outlets being of equal cross sectional area, the signal derived from said means responsive to the turbine shaft speed being supplied into the space under the imperforate diaphragm one of said transducers and the operating pressure fluid being supplied to the nozzles of the summation means with the signal to be transformed being taken from the space above the imperforate diaphragm.

References Cited UNITED STATES PATENTS 2,126,533 8/1938 Caughey 137-36 2,258,136 10/1941 Folgmann 137-36 2,823,686 2/1958 Anderson 137-36 3,306,031 2/1967 Moiroux 137-36 3,332,431 7/1967 Linder 137-36 3,342,196 9/1967 Przybylko 137-36 3,373,757 3/1968 Watson 137-36 CARROLL B. DORITY, 111., Primary Examiner US. Cl. X.R. 

